Axons will be isolated from bovine and rat CNS as myelin-free entities derived from myelinated axons and their protein and lipid composition determined. These data will be compared with bovine perikarya and rat perikarya to determine how the lipids (particularly the sphingolipids cerebroside and sulfatide) are partitioned between the perikaryal and axonal compartments of the neuron. The ability of isolated axons and perikarya to synthesize sphingolipids will be investigated. In vivo experiments will also be performed to determine the turnover of sphingolipids in the axonal and perikaryal compartments of the neuron. Finally an axolemma preparation derived from myelinated axons will be isolated and characterized.